[Objective] Analyzing the scale effects of runoff and sediment in Jinghe River basin and comparing the changes of scale effect of runoff and sediment before and after mutation

the mutation time point was determined by mutation testing in order to provid support for the study of climate change and human activities on runoff and sediment scale effects.[Methods] Collecting runoff and sediment data from 15 hydrostations within the Jinghe River basin during 1958-2013

based on the characteristics of runoff and sediment come from different sources

the Jinghe River basin was divided into northern branch and south branch to explore the scale effects of the two branches of the water and sediment. Then the Mann-Kendall shift testing method was adopted to calculate the mutation point of runoff and sediment in time

the scale effects of runoff and sediment before and after abrupt change were compared to seek similarities and differences.[Results] (1) The scale effects of runoff and sediment had a reverse relationship between northern branch and southern branch. Runoff of the north branch(Hongde-Zhangjiashan) was increased linearly with area. Runoff of the south branch (Sanguankou-Zhangjiashan) showed a logarithmic function relationship with area

runoff modulus was decreased rapidly at first and then decreased slowly. Sediment of the north branch was decreased linearly with area increasing

while sediment of south branch showed a power function relationship with area

namely specific sediment yield was increased firstly and then decreased slowly with area increasing; (2) Runoff and sediment within two branches had different degree of reduced after abrupt change. Most of scale effects kept the same fitting function as before abrupt change

only specific sediment yield of the south branch alters the optimal fitting from binomial function to linear function.[Conclussion] The scale effects of runoff and sediment of Jinghe River basin had been changed by climate change and human activities.